SINGAPORE (Reuters) - The Olympic Council of Asia must move fast to find a replacement city to host the 2019 Asian Games, International Olympic Committee Vice President Ng Ser Miang told Reuters on Friday, but ruled out his suitable Singapore homeland as an option.

Vietnam's government announced their surprise decision on Thursday to quit as hosts of the event in their capital Hanoi, citing a lack of preparedness and concerns that holding the multi-sport event for the first time would not prove financially viable.

Wealthy Singapore will host the much smaller SEA Games in 2015 for 11 Southeast Asian countries in their soon to open $1 billion sports hub, which includes a 55,000 seat stadium, and 6,000 capacity aquatics centre, but were not seeking any extra work load at short notice.

"With the process of selecting a city and preparing the city for the Games, time is of essence as we are only five years away," Ng said in a statement sent to Reuters.

"We are putting all our resources and energy to ensure a successful SEA Games. A bid for 2019 Asian Games is not on the cards at the moment."

Hanoi was awarded the Games in November 2012 ahead of the Indonesian city of Surabaya but the cost of hosting the event, which economists have estimated could be as high as $500 million, was an issue.

Indonesian Olympic officials also voiced concerns about the likely increased price when asked if they were interested in rebidding.

"We have to realize that budgeting to host such an event will be different by now," Indonesia Olympic Committee chairperson Rita Subowo told Reuters via telephone.

"The government of Indonesia may be ready to take over, but what about the hosting city? We are happy that Surabaya is the hosting city of the 2021 Asian Youth Games, but we will discuss about 2019."

SURPRISED

The Asian Games, which was held for the first time in 1951, has grown to consist of around 40 sports with athletes from 45 countries taking part putting pressure on host nations to build infrastructure and accommodation as well as stadiums.

It will be held in Incheon, South Korea this year after China hosted the last edition and wealthy Qatar before them in 2006.

Although Vietnam's $155 billion economy is in recovery and annual growth of more than five percent is expected in the next few years, it faces many deep-rooted problems, including weak infrastructure, one of Asia's highest levels of bad debt and a state sector mired in graft and inefficiency.

Prime Minister Nguyen Tan Dung held a meeting with officials on Thursday and concluded it was better to opt out now, because poor preparation could damage Vietnam's reputation and that the state budget could be invested "in other very urgent tasks."

India, which has hosted the Asian Games twice, are still reeling from the cost and scandal surrounding their somewhat chaotic hosting of the 2010 Commonwealth Games in New Delhi where preparations were heavily criticised.

The OCA told Reuters on Friday they were still waiting for official confirmation from Vietnam of their withdrawal and would not discuss potential hosts of the 18th Asian Games before receiving it.

Ng, who failed in his bid to become the first Asian president of the IOC in September, said he understood Vietnam's position.

"According to Prime Minister Nguyen, the decision to withdraw is due to Vietnam suffering the impact of global recession, hence will not be able to do a good job," he said.